It is widely expected that in the future many manufactured products will be completely or partially manufactured by robots and other programmable machines. The part of the robot or programmable machine that actually contacts the part to be manipulated is referred to as an end effector. An end effector is typically used for one of two basic operations: gripping and manipulating a workpiece or performing a manufacturing operation such as welding or painting. The present invention is concerned with the first category of end effector, known as a gripper.
A potential major application of robots and programmable machines generally is in automated assembly requiring gripping and manipulation of an assembly part. Although sophisticated programmable machines are available to perform the required complex manipulations, known gripper designs are typically limited in their ability to handle different shaped parts encountered in an assembly operation, and most grippers are designed to handle only a single part or a family of similarly shaped parts.
One solution to this problem is to provide individual grippers arranged in racks within reach of the robot arm, with the machine being programmed to manipulate the arm to change one gripper for another as desired. However, this increases the time required for an assembly operation, and hence necessarily increases the cost of assembly as well.
A better solution in terms of time and cost factors is a universal gripper capable of manipulating and gripping different shaped parts. While there have been attempts to design a universal gripper to operate in the manner of a human hand, as of yet such designs have not proved successful. Moreover, the requirement that such a gripper have variable gripping forces will necessarily complicate its use.
It is therefore desirable to provide a gripper assembly incorporating a gripper capable of manipulating different shaped parts, and to provide a programmable machine incorporating such a gripper assembly, with the machine being preprogrammed to manipulate the gripper assembly as required to grasp and release the different shaped parts.